With the continuous development of the economy, the traffic situation in major cities is gradually congested. With its advantages of speed and comfort, the subway has gradually become an effective way to solve urban traffic problems. Therefore, almost all cities have a very dense concentration of people in subway stations and subway trains. If there is a sudden accident at this time, such as transmission system failure, fire, etc., how to quickly and orderly organize the evacuation of passengers from the section tunnel as soon as possible, and eliminate or reduce the casualties caused by the unobstructed evacuation channel?
At this time, the role of the subway evacuation platform is reflected. The main function of the evacuation platform is the evacuation of personnel, and it is a safe passage that must be equipped in the subway tunnel. It is fixed on the side wall of the tunnel through the support support, and the height is equal to or lower than the ground of the subway train car, and you can directly step on the evacuation platform and go to the nearest safe station along the evacuation platform. In order to ensure the effectiveness and safety of the evacuation platform, its performance is also required.
Under the premise of satisfying the bearing strength, the evacuation platform also needs to have the properties of moisture resistance, corrosion resistance, aging resistance, electrical insulation, fire performance, high flame retardancy, low smoke and non-toxicity, and surface anti-slip to ensure that it will not be damaged or collapsed in the case of multi-person running and crowding in the evacuation situation, so as to ensure timely and smooth evacuation and protect the safety of passengers. Therefore, the following items are mandatory items for subway evacuation platforms.
Impact performance test
The impact test is to determine the ability of a material to absorb energy during a collision, which can determine the toughness, impact strength, fracture resistance, etc. of the material.
The impact test method of the subway evacuation platform is to support the specimen on the wooden ridge that meets the requirements in the length direction, and then the sandbag falls freely at a height of 1m from the specimen, and the impact height should be continuously impacted at the geometric center of the specimen for 5 times, and the impact height should be the vertical distance from the bottom of the sandbag to the impact surface of the specimen.
Salt spray corrosion resistance test
The salt spray test is to assess the salt spray corrosion resistance quality of the material, which is the key to measure the salt spray corrosion resistance quality of the material.
The salt spray corrosion resistance test of the subway evacuation platform is to place the specimen in the salt spray box first, so that the plane and horizontal plane of the test specimen are at an angle of 60°~75°. With 24h as a cycle, continuous spraying for 8h, and then stop for 16h, a total of 5 cycles were tested. After the test, the sample was taken out and placed at room temperature for 24h, and then the bearing performance test was carried out to record the deflection value of the center of the platform.
Load-bearing performance test
Place the specimen horizontally on the bracket, note that the center of the specimen should be in the center of the span of the bracket, and the surface of the specimen should be consistent with the actual application. During the test, lay the steel plate on the upper surface of the specimen, pay attention to the edges of both ends of the steel plate should not exceed the fulcrum, and then evenly apply the weight on the steel plate, the total load of the specimen should be 5kPa, keep it for 30min, and record the deflection value of the center of the platform.
Combustion performance test
Combustible properties refer to all physical and chemical changes that occur when a material is burned or exposed to fire. The combustion class of the material is determined by conducting a combustion test.
During the test, the prepared and condition-adjusted specimen should be put into the specimen frame, and the specimen frame should be suspended on the supporting part. Insert the specimen holder into the specified position in the furnace, and start the timer immediately when the specimen is located in the specified position in the furnace. The temperature measured by the thermocouple in the furnace during the test is recorded. Carry out 30min test to judge whether the temperature in the furnace is balanced, the balance can stop the test, and the test should continue until the temperature balance or the test time reaches 60min. Note: Record the occurrence of continuous flames during the test and for how long.
Fire resistance test
The fire resistance test is to simulate different fire conditions through test equipment to evaluate the fire resistance of materials.
Within 5 minutes before the start of the test, the initial temperature records of all thermocouples are checked and the data is recorded. After ignition, when the thermocouple in the test furnace near the center of the test piece records 50°C, it should be used as the test start time. The temperature test is carried out first, and then the test piece after the temperature test and natural cooling is taken out of the test furnace and placed horizontally. The specimen should bear 6 points of concentrated load, 0.65kN should be loaded on each stress point, and it should be kept for 30min after the loading is completed, and the deformation value in the vertical direction of the center point of the specimen should be measured and recorded every interval of no more than 5min. Observe and record during the test.
The commonly used subway evacuation platform is divided into two kinds according to the different materials of its main body, one is a cement-based evacuation platform, and the other is a composite evacuation platform. Compared with the cement-based evacuation platform, the composite evacuation platform has the advantages of light weight, high strength, on-site cutting, and easy installation, so it is more favored. However, due to the heavy burden of safe dredging of the subway evacuation platform, the state has high technical requirements for it, so no matter what kind of evacuation platform needs to be strictly tested before it can be put into use.